This invention relates generally to transparencies, and more specifically the present invention is directed to transparencies, that is a transparent substrate film for receipt of a toner image and the resulting image transparency, containing an oil absorbing polymer with an ink receiving layer thereon, and the use of these transparencies in Dot Matrix printers such as the commercially available Roland PR-1012. Thus, in one embodiment, the present invention relates to transparent substrates for receipt of a toner image comprised of a supporting substrate, an oil absorbing polymer, on one or both sides thereof, and an ink receiving polymer thereover, which polymer can be present on one or both (two) sides or exposed horizontal surfaces of the oil absorbing layer.
Single strike ribbons for Dot Matrix printers comprised of a fabric such as nylon, a polyester, or silk doped with mineral or vegetable oil-based dyes are known. Also, known are multistrike ribbons which are comprised of blends of carbon black and rape seed oil, reflex blue pigment, and lecithin as a surfactant. The aforementioned inks are, for example, difficult to dry on conventional transparencies, and therefore require specially coated polyester transparencies when selected for overhead projectors. The aforementioned disadvantage is avoided with the transparencies of the present invention. Other advantages associated with the transparencies in many embodiments of the present invention include high optical densities of, for example, from about 0.9 to about 1.15, and images thereon that dry in less than 60 seconds.
Transparencies, including typewriter ribbon transparencies, are known, reference for example U.S. Pat. Nos. 3,002,858; 4,379,804; 4,461,793; 4,474,850; 4,503,111; 3,790,435; 4,233,354 and 4,301,195. More specifically, there is illustrated in U.S. Pat. No. 4,301,195 a transparent sheet material comprised of a transparent backing having an ink receptive stratum thereon containing, for example, a mixture of two polymers, or individual layers of each polymer. One of the aforementioned selected polymers is obtained by the reaction of an epoxidized water insoluble neutral rubbery polymer and a water soluble secondary monoamine, reference the Abstract of the Disclosure. In the '858 patent, the disclosure of which is totally incorporated herein by reference, there is illustrated an ink receptive coating composition capable of receiving a typewritten image, wherein there can be selected as a coating ethyl cellulose, and a substrate such as Mylar. Reference to column 1, line 12, of this patent indicates that the plastics referred to, upon which it is intended to present images, include transparent, translucent, or opaque sheets, and laminated structures. Also, in the aforementioned '354 patent, there are illustrated printed polyester films with certain properties; and containing on its surface a well adhering printed layer formed by a printing ink with a cellulose derivative as a binder. In the '435 patent, there is described synthetic writing paper comprised of a Mylar base, and a coating thereover including poly(styrene).
Other transparencies similar to those illustrated in the 4,301,195 patent are disclosed in U.S. Pat. Nos. 4,474,850 and 4,503,111. Furthermore, there are disclosed in U.S. Pat. No. 4,461,793 coatings that can be applied to a heat shrinkable base material which is capable of forming a printing layer thereon. Specifically, in column 2, line 1, of this patent there is illustrated a printable coating useful for application to heat shrinkable identification devices containing a polyester film, calcium carbonate, and a silicate compound. Apparently, the heat shrinkable base material of the '793 patent is useful as a receiver for typewritten images.
Furthermore, in U.S. Pat. No. 4,701,367, the disclosure of which is totally incorporated herein by reference, there is described a typewriter transparency with, for example, a supporting substrate and thereover a coating blend selected from the group consisting of (1) poly(vinyl methyl ether), and poly(styrene); (2) poly(vinyl methyl ether), poly(styrene) and poly(ethyl acrylate); (3) a styrene-(ethylene-butylene)-styrene triblock copolymer; (4) poly(vinyl acetate), and poly(vinyl isobutylether); (5) a styrene-butadiene-styrene triblock copolymer; (6) poly(vinyl methyl ether), poly(vinyl acetate), and poly(ethylacrylate); (7) poly(hexyl methacrylate) and poly(ethyl methacrylate), and other coatings.
There is disclosed in U.S. Pat. No. 4,446,174 an ink jet recording method for producing a recorded image on an image receiving sheet with aqueous inks, and wherein an ink jet is projected onto an image receiving sheet comprising a surface layer containing a pigment, which surface layer is capable of adsorbing a coloring component present in the aqueous ink. Also, there is disclosed in U.S. Pat. No. 4,371,582 an ink jet recording sheet containing a latex polymer, which can provide images having excellent water resistance properties and high image density by jetting them onto an aqueous ink containing a water soluble dye. Similarly, U.S. Pat. No. 4,547,405 describes an ink jet recording sheet comprising a transparent support with a layer comprising 5 to 100 percent by weight of a coalesced block copolymer latex of poly(vinyl alcohol) with polyvinyl(benzyl ammonium chloride), and 0 to 95 percent by weight of a water soluble polymer selected from the group consisting of poly(vinyl alcohol), poly(vinyl pyrrolidone), and copolymers thereof.
Other coatings for ink jet transparencies include blends of carboxylated polymers with poly(alkylene glycol), reference U.S. Pat. No. 4,474,850; blends of poly(vinyl pyrrolidone) with matrix forming polymers such as gelatin; or poly(vinyl alcohol) swellable by water and insoluble at room temperature but soluble at elevated temperatures, reference U.S. Pat. No. 4,503,111; and blends of poly(ethylene oxide) with carboxymethyl cellulose as illustrated in U.S. Pat. No. 4,592,954, the disclosure of which is totally incorporated herein by reference. In the aforementioned 4,592,954 patent, there are mentioned U.S. Pat. Nos. 4,273,602; 4,370,379 and 4,234,644. Disclosed in the '602 patent are heat sensitive recording materials comprised of a support sheet of a thickness of from 5 to 40 microns containing thereon a heat sensitive transfer layer with a phenolic material, a colorless or precolored component which reacts with the phenolic to form a color upon application of heat, and a heat fusible material with a melting point of 40.degree. to 150.degree. C. It is indicated in this patent that heat sensitive transfer layers can be formed from waxes, or resins of a low molecular weight with colored dyes dispersed therein; however, apparently there are problems associated with such a method in that part of the layer transfers to ordinary paper causing undesirable staining and a decrease in contrast between the letters and the background. Accordingly, the recorded letters cannot be easily read, a disadvantage avoided with the transparencies of the present invention.
Also known is the preparation of transparencies by electrostatic means, reference U.S. Pat. No. 4,370,379, wherein there is described the transferring of a toner image to a polyester film containing, for example, a substrate and a biaxially stretched poly(ethylene terephthalate) film, including Mylar. Moreover, in U.S. Pat. No. 4,234,644 there is disclosed a composite lamination film for electrophoretically toned images deposited on a plastic dielectric receptor sheet comprising in combination an optically transparent flexible support layer, and an optically transparent flexible intermediate layer of a heat softenable film applied to one side of the support; and therein the intermediate layer possesses good adhesion to the support.
There were listed in a patentability search report the following prior art:
U.S. Pat. No. 4,713,280, the disclosure of which is totally incorporated herein by reference, discloses a transparent sheet capable of receiving oil-based inks from impact ink transfer printers that use fabric ribbon. The ink receptive layer may comprise polyvinyl butyral and a particulate material such as amorphous silicon for better ink retention; U.S. Pat. No. 4,269,891 discloses a transparency with an ink absorbing layer containing a number of white pigments such as silica and titanium dioxide. A binder layer of the transparency is comprised of polyvinyl alcohol; U.S. Pat. No. 4,474,850 discloses a polyester film (Mylar type) coated with vinyl acetates containing pigments such as silica, zinc oxide and calcium carbonate for better ink retainment; U.S. Pat. No. 4,701,367 presented hereinbefore; and U.S. Pat. No. 4,781,985 discloses an ink jet transparency coating comprising polyvinyl pyrrolidone/polyvinyl acetate copolymer.
Although the transparencies illustrated in the prior art are believed to be suitable for their intended purposes, there remains a need for other transparencies containing developed images that are useful for oil based ribbons, and that will enable the formulation of images with high optical densities. Additionally, there is a need for transparencies containing developed images with an oil absorbing polymer layer that are compatible with ink compositions, including those compositions selected for Dot Matrix printers, and particularly those derivable from blends of carbon black with rape seed oil, reflex blue pigment and lecithin components. There is also a need for transparencies containing developed images that enable the rapid drying of inks, and wherein, subsequent to drying, image smearing is avoided, or substantially minimized. Another need of the present invention resides in providing transparencies with coatings that do not block (stick) at, for example, 50 percent relative humidity and at a temperature of 50.degree. C. in many embodiments.